Terry--Steve sorta sounded like it was pretty much decided that he was going Type I.
Of course the type IV is a brute and scoots up mountains like they weren't there. On our 2,600 mile trip to Carlisle and back home to Hot Springs through D.C, Richmond and Charlotte, we went over the Smokies outside Asheville effortlessly.
I swapped my 1915 for a 2,143cc Raby Tyope IV and went from a top speed of 95+/- to 142 (on a dyno) with torque of 132 from 3,100 RPMs all the way to 7,000. We averaged 25 MPG for the whole trip with best MPG of 27.6 near Christiansburg, VA in the mountains.
The Type IV isn't for everyone but it works well for me.
Russ's 911 (250 hp) couldn't catch Cory in his Type IV powered Hoopty going up I 81 on the way to Carlisle. No doubt Hoopty's light weight of 1,200 # helped some too.